1091.

The Red Sea. (1091. 1092).

For a long time the water of the Mediterranean flowed out through
the Red Sea, which is 100 miles wide and 1500 long, and full of
reefs; and it has worn away the sides of Mount Sinai, a fact which
testifies, not to an inundation from the Indian sea beating on these
coasts, but to a deluge of water which carried with it all the
rivers which abound round the Mediterranean, and besides this there
is the reflux of the sea; and then, a cutting being made to the West
3000 miles away from this place, Gibraltar was separated from Ceuta,
which had been joined to it. And this passage was cut very low down,
in the plains between Gibraltar and the ocean at the foot of the
mountain, in the low part, aided by the hollowing out of some
valleys made by certain rivers, which might have flowed here.
Hercules 605
came to open the sea to the
westward and then the sea waters began to pour into the Western
Ocean; and in consequence of this great fall, the Red Sea remained
the higher; whence the water, abandoning its course here, ever after
poured away through the Straits of Spain.

Footnotes

262:605 9: Leonardo seems here to mention Hercules half
jestingly and only in order to suggest to the reader an allusion to
the legend of the pillars of Hercules.